Coordinate axis drive system for a coordinatograph

ABSTRACT

This specification describes a control system for a twodimensional scanner head in a coordinatograph. A closed electrical circuit comprising a synchrotorque transmitter and a synchrotorque receiver is used to power the scanner assembly along coordinate one axis. Another closed electrical circuit comprising a control transmitter and a control transformer power the scanner assembly in the direction of a second coordinate axis. The friction forces involved in effecting incremental adjustments in the direction of the second axis are higher than the corresponding forces developed in the adjustment in the direction of the first axis.

United States Patent lnventor William A. Ford Southl'ield, Mich.

App]. No. 717,850

Filed Apr. 1, 1968 Patented Apr. 6, 1971 Assignee Ford Motor CompanyDearborn, Mich.

COORDINATE AXIS DRIVE SYSTEM FOR A COORDINATOGRAPH 11 Claims, 61 DrawingFigs.

US. Cl. l78/6.8, 346/3 3 Int. Cl. H04n 5/30 Field of Search 346/33(MCR); 250/202; 178/68 References Cited UNITED STATES PATENTS Eller.....318/30 3,032,881 5/1962 Fengler 33/23 3,105,907 10/1963 Colten et al.250/202 3,178,717 4/1965 Fengler 346/33 3,398,452 8/1968 Little et al.33/18 Primary Examiner-Robert L. Griffin Assistant Examiner-Richard K.Eckert, Jr. Att0rneysJ0hn R. Faulkner and Donald J. l-larrintonABSTRACT: This specification describes a control system for atwo-dimensional scanner head in a coordinatograph. A closed electricalcircuit comprising a synchrotorque transmitter and a synchrotorquereceiver is used to power the scanner assembly along coordinate oneaxis. Another closed electrical circuit comprising a control transmitterand a control transformer power the scanner assembly in the direction ofa second coordinant axis. The friction forces involved in effectingincremental adjustments in the direction of the second axis are higherthan the corresponding forces developed in the adjustment in thedirection of the first axis.

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1. A contour data recording system comprising a draft plate supportingtable (10), a coordinate X-axis and Y-axis carrier assembly comprising acarriage beam (90) extending over the plane of said table (10) in closeproximity thereto and in parallel disposition therewith, said beam (90)being situated with its principal geometric axis in the direction of thecoordinate Yaxis, a crossmember (44) supporting one end of said beam(90), said crossmember (44) being movably mounted on said table (10) onone margin thereof, the motion of said crossmember (44) in the Xaxisdirection, an electrical impulse generator (130) carried by said beamand drivably coupled thereto whereby it is adapted to generate anelectrical impulse voltage for each increment of movement of saidgenerator in the Y-axis direction, a carrier (104) movably mounted onsaid beam (90) and supporting said impulse generator (130), an opticalscanner (128) carried by said carrier (104), a second impulse voltagegenerator (74) carried by said crossmember (44), said second impulsegenerator being coupled drivably to said table (10) whereby it isadapted to generate a voltage impulse for each increment of movement ofsaid beam (90) in the X-axis direction, synchronous driving and drivenelectrical units (186,290) each having multiple coil stators (360,362)connected together electrically and electrical rotor windings (364,366)cooperating with their respective stators in phased relationship, aforce transmitting driving connection between the rotor windings of onesynchronous unit and said carrier, and operator-controlled drive means(298) for rotating the rotor windings for the other synchronouselectrical unit whereby Y-axis adjustments of said scanner can beaccomplished.
 2. The combination as set forth in claim 1 including asecond pair of synchronous electrical units (248,290) with stators (368,370) having movable coils connected electrically and cooperating woundrotors whereby manual displacement of the rotor of one of said secondpair of units with respect to its stator results in the generation of atorque on the rotor of the other of said second pair of units, means(133) for drivably connecting mechanically the rotor of the other ofsaid second pair of units to said crossmember whereby X-axis adjustmentsof said beam can be accomplished, and means (324) for manually adjustingthe angular position of the rotor of the first of said second pair ofunits.
 3. The combination as set forth in claim 2 wherein the electricalsynchronous unit carried by the crossmember comprises a controltransformer and its associated electrical unit comprises a torquetransmitter, the control transformer and said torque transmitter eachhaving electrically-connected, multiple-winding, stationary stators anda movable wound rotor, the rotor of the torque transmitter beingconnected mechanically to said manually adjusting means, the rotor ofsaid control transformer being connected mechanically to saidcrossmember whereby the latter sends to said rotor a position feedbacksignal, a servomotor having an armature and a stator, the stator of saidservomotor being connected electrically to the rotor of said controltransformer, said last-mentioned connection including a voltageamplifier adapted to magnify the error signal generated in the rotorwindings of said control transformer, and a mechanical connectionbetween the armature for said servomotor and said crossmember wherebysaid scanner is adjusted in either X-axis direction depending upon thedirection of rotation of the rotor of said control transformer.
 4. Thecombination as set forth in claim 3 wherein the armature of saidservomotor is connected to a DC tachometer voltage generator, the outputof said tachometer generator being connected to the input side of saidamplifier, the input side of said amplifier, the output side of saidtachometer generator and the output side of said control transformerrotor being connected together at a voltage summing point whereby theoutput voltage of said tachometer generator opposes the error signalvoltage generated by said control transformer as the rotor of saidtorque transmitter is displaced by the operator with respect to itsstationary stator.
 5. The combination as set forth in claim 3 whereinsaid scanner comprises a television camera carried by said carrier, saidcamera having a lens situated directly over the surface of said table onone side of said beam, a television monitor circuit for receiving thesignals of said camera whereby the operator may observe the position ofsaid lens with respect to a target point, a position digitizer circuitmeans for recording the coordinant values of selected points scanned bysaid scanner, said digitizer being connected electrically to each ofsaid voltage impulse generators whereby the individual voltage impulsesare counted and recorded to permit location of selected points withrespect to a predefined origin point in terms of both X-axis coordinantand Y-axis coordinant.
 6. A contour data recording system comprising adraft plate supporting table, a coordinate X-axis and Y-axis carrierassembly comprising a carriage beam extending over the plane of saidtable in close proximity thereto and in parallel disposition therewith,said beam being situated with its principal geometric axis in thedirection of the coordinate Y-axis, a crossmember supporting one end ofsaid beam, said crossmember being movably mounted on said table on onemargin thereof, the direction of motion of said crossmember beingparallel to the X-axis direction, an electrical impulse generatorcarried by said beam and drivably coupled thereto whereby it is adaptedto generate an electrical impulse voltage for each incremental movementthereof in a Y-axis direction, a carrier movably mounted on said beamand supporting said impulse generator, an optical scanner carried bysaid carrier, a second impulse voltage generator carried by saidcrossmember, said second impulse generator being coupled drivably tosaid table whereby it is adapted to generate a voltage impulse for eachincremental movement of said beam in an X-axis direction, synchronousdriving and driven electrical units each having multiple coil statorsconnected together electrically and electrical rotor windingscooperating with their respective stators in phased relationship, one ofsaid driven electrical units being mounted on said crossmember andanother being mounted on said carrier, a first torque transmittingdriving connection between the windings of a first synchronous unit onsaid crossmember and said carrier, a second torque transmitting drivingconnection between the windings of a second synchronous unit on saidcarrier and said beam, and operator-controlled drive means for rotatingthe windings for each of the other synchronous electrical units wherebymanual Y-axis adjustments and X-axis adjustments of said scanner can beaccomplished, the drive means for driving the windings of said otherunits comprising both a coarse adjustment hand element and a fineadjustment hand element connected drivably to the associated windings,said drive means including speed reducing gears between one of said fineadjustment hand elements and its associated rotor windings to permitincreased sensitivity in the adjustment of said scanner in the Y-axisdirection.
 7. A contour data recording system comprising a draft platesupporting table, a coordinate X-axis and Y-axis carrier assemblycomprising a carriage beam extending over the plane of said table inclose proximity thereto and in parallel disposition therewith, said beambeing situated with its principal geometric axis in the direction of thecoordinate Y-axis, a crossmember supporting one end of said beam, saidcrossmember being movably mounted on said table on one margin thereof,the direction of motion of said crossmember being parallel to the X-axisdirection, an electrical impulse generator carried by said beam anddrivably coupled thereto whereby it is adapted to generate an electricalimpulse voltage for each incremental movement thereof in a Y-axisdirection, a carrier movably mounted on said beam and supporting saidimpulse generator, an optical scanner carried by said carrier, a secondimpulse voltage generator carried by said crossmember, said secondimpulse generator being coupled drivably to said table whereby it isadapted to generate a voltage impulse for each incremental movement ofsaid beam in an X-axis direction, two synchronous driving electricalunits and two synchronous driven electrical units, each having multiplecoil stators the stators of one driving unit and one driven unit beingconnected together electrically, the stators of the other driving unitand the other driven unit being connected together electrically,electrical rotor windings cooperating with each stator in phasedrelationship, one driven unit being mounted on said crossmember and theother driven unit being mounted on said carrier a torque transmittingdriving connection between the windings of said one driven unit and saidcarrieR, and operator controlled drive means for rotating the windingsfor the synchronous driving electrical units whereby Y-axis adjustmentsand X-axis adjustments of said scanner can be accomplished, anothertorque transmitting driving connection between the windings the otherdriven unit and said crossmember, said drive means comprising separatecoarse adjustment hand elements connected to the respective rotorwindings with a first driving ratio and a fine adjustment hand elementand a speed-reducing gearing between said fine adjustment hand elementand its associated rotor.
 8. The combination as set forth in claim 6wherein the electrical synchronous unit carried by the crossmembercomprises a control transformer and its associated electrical unitcomprising a torque transmitter, the control transformer and said torquetransmitter each having electrically-connected, multiple-winding,stationary stators and a movable wound rotor, the rotor of the torquetransmitter being connected mechanically to the associated drive means,the rotor of said control transformer being connected mechanically tosaid crossmember, a servomotor, an electrical connection between saidservomotor and the rotor of said control transformer, saidlast-mentioned connection including a voltage amplifier adapted tomagnify the error signal generated in the rotor windings of said controltransformer, and a mechanical connection between said servomotor andsaid crossmember whereby said scanner is adjusted in either X-axisdirection depending upon the direction of rotation of the rotor of saidcontrol transformer.
 9. The combination as set forth in claim 8 whereinthe connection between said servomotor and said crossmember comprises aspeed-reducing gear assembly the input element of which is connected tosaid servomotor, and drive elements connected to the output element ofsaid gear assembly comprising a flexible member connected to saidcrossmember and trained over one of said drive elements and extending ina plane parallel to the plane of said table.
 10. The combination as setforth in claim 7 wherein said scanner comprises a television cameracarried by said carrier, said camera having a lens situated directlyover the surface of said table on one side of said beam, a televisionmonitor circuit for receiving the signals of said camera whereby theoperator may observe the position of said lens with respect to a targetpoint, and a position digitizer circuit means for recording thecoordinate values of selected points scanned by said scanner, saiddigitizer being connected electrically to each of said voltage impulsegenerators whereby the individual voltage impulses are counted andrecorded to permit location of selected points with respect to apredefined origin point in terms of both X-axis coordinate and Y-axiscoordinate.
 11. The combination as set forth in claim 9 wherein saidscanner comprises a television camera carried by said carrier, saidcamera having a lens situated directly over the surface of said table onone side of said beam, a television monitor circuit for receiving thesignals of said camera whereby the operator may observe the position ofsaid lens with respect to a target point, and a position digitizercircuit means for recording the coordinate values of selected pointsscanned by said scanner, said digitizer being connected electrically toeach of said voltage impulse generators whereby the individual voltageimpulses are counted and recorded to permit location of selected pointswith respect to a predefined origin point in terms of both X-axiscoordinate and Y-axis coordinate.